TFT-LCD having pixel electrode overlapping scan and data lines except at the intersection of lines

ABSTRACT

A structure is provided which avoids overlap of a pixel electrode and an intersecting portion of a gate line and a data line. For example, the pixel electrode is patterned such that its corner portion is intentionally cut out to avoid the intersecting portion. With this structure, the capacitance of a storage capacitor that is formed by an overlapping portion of the pixel electrode and a black matrix can be increased while short-circuiting in a third interlayer insulating film that is interposed between the pixel electrode and the black matrix is prevented.

This application is a divisional of Ser. No. 08/822,789 filed Mar. 24,1997 now U.S. Pat. No. 6,222,595.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device inwhich semiconductor devices using a thin-film semiconductor havingcrystallinity are arranged. In particular, the invention relates to anactive matrix liquid crystal display device.

2. Description of the Related Art

In recent years, technologies for forming thin-film transistors (TFTs)on an inexpensive glass substrate have developed at high speed. This isdue to increase in demand for the active matrix liquid crystal displaydevice in which integrated circuits are formed on the same substrate.

In the active matrix liquid crystal display device, hundreds ofthousands or more of pixels arranged in matrix form are respectivelyprovided with thin-film transistors and charge entering/exiting fromeach pixel electrode is controlled by the switching function of thethin-film transistor.

The active matrix liquid crystal display device has a feature thatintegrated circuits are formed in which the thin-film transistorsarranged in matrix form in the pixel area (i.e., pixel TFTs) are drivenby driver circuit thin-film transistors (i.e., driver TFTs) that areprovided around the pixel area.

However, to allow the active matrix liquid crystal display device tofunction properly, it is necessary that all the thin-film transistors inthe pixel area operate normally. This is a factor of greatly reducingthe yield of a manufacturing process of the active matrix liquid crystaldisplay device.

Among causes of display defects in the pixel area are an operationfailure of a pixel TFT and short-circuiting between wiring lines. Inparticular, the problem of short-circuiting between wiring lines shouldbe solved thoroughly because it may cause a point defect or a linedefect.

Among various types of electrodes and wiring lines provided in theactive matrix liquid crystal display device are a gate line, a dataline, a capacitor line, a black matrix, and a pixel electrode. Theseelectrodes and wiring lines are made of conductive materials andinsulated from each other by an interlayer insulating film.

However, for example, in a step portion where the coverage of aninterlayer insulating film is poor, there may occur a case thatsufficient insulation performance is not obtained because, for instance,a current path is formed between wiring lines due to insufficientthickness of the interlayer insulating film, a crack in the interlayerinsulating film, or some other reason.

Process Leading to the Invention

FIGS. 1A and 1B show a general structure of an intersecting portion of agate line and a data line and its vicinity in an active matrix liquidcrystal display device in which a black matrix is formed on the samesubstrate as the pixel area. FIG. 1A is a sectional view taken alongline A-A′ in FIG. 1B.

Reference numerals 101-103 denote a glass substrate, an undercoat film,and an insulating film extending from a gate insulating film,respectively. A gate line 104 is formed on the insulating film 103, anda first interlayer insulating film 105 is so formed as to cover the gateline 104. A data line 106 is formed on the first interlayer insulatingfilm 105.

A second interlayer insulating film 107 is so formed as to cover thedata line 106, and a black matrix 108 is formed on the second interlayerinsulating film 107. The black matrix 108 is covered with a thirdinterlayer insulating film 109, and a pixel electrode 110 is formedthereon. A thin film 111 as an alignment film is formed on the pixelelectrode 110.

FIG. 1B is a top view of an intersecting portion 100 of the gate line104 and the data line 106. In FIG. 1B, the gate line 104 and the dataline 106 are drawn by broken lines because they exist below the blackmatrix 108.

As mentioned above, the pixel electrode 110 is formed above the blackmatrix 108 with the third interlayer insulating film 109 interposed inbetween. In this structure, a capacitor is formed by the black matrix108 and the pixel electrode 110. The present inventors utilize thiscapacitor as an auxiliary capacitor.

Therefore, to increase the capacitance of the auxiliary capacitor, it isdesirable that the overlapping portion of the black matrix 108 and thepixel electrode 110 be as wide as possible. However, if the pixelelectrode 110 is so formed as to overlap with the intersecting portion100, the following problems will occur.

In FIG. 1A, reference numerals 112 and 113 denote spacers to determinethe cell gap of the liquid crystal display device. The spacers 112 and113 are interposed between and pressed by the active matrix substrate(which means the glass substrate 101 and the device structure formedthereon collectively) and an opposed substrate 114.

The spacers 112 and 113 are arranged at a certain density on the surfaceof the active matrix substrate (or the opposed substrate). For example,in the case of a small liquid crystal display device having a diagonalsize of about 3 inches, they may be distributed at a density of severaltens of pieces per square centimeters. However, as the size of theliquid crystal display device increases, the density needs to beincreased in a range of several tens to several hundreds of pieces persquare centimeters.

Since the spacers exist at a given density in the pixel area of theactive matrix display device, a spacer may be located at theintersecting portion 100 of the gate line 104 and the data line 106 at acertain probability.

In this case, since the intersecting portion 100 of the gate line 104and the data line 106 considerably protrudes from the flat portion, thespacer 112 placed thereon receives much stronger pressure than thespacer 113 which is placed on the flat portion.

The strong pressure exerted on the spacer 112 in turn imposes a heavyload on the underlying laminate structure, to possibly cause break-offportions 115 such as a crack in the third interlayer insulating film109. As a result, a current path is formed between the black matrix 108and the pixel electrode 110, so that they no longer has the function offorming an auxiliary capacitor. This may causes an image display defect.

It is easily understood that the above defect is caused by the structurein which the pixel electrode 110 is laid on the highest portion of thestep as shown in FIG. 1A, and hence the problem can be solved byavoiding such a structure.

On the other hand, to increase the capacitance of the auxiliarycapacitor, it is necessary to make the overlapping portion of the blackmatrix 108 and the pixel electrode 110 as wide as possible. In the abovecircumstances, the inventors thought that it would be proper to providea structure shown in FIG. 2A.

FIG. 2A is a top view corresponding to FIG. 1B. FIG. 2A therefore usesthe same reference numerals as FIG. 1B.

In this structure, the pixel electrode 110 does not overlap with thegate line 104 nor the data line 106. That is, the pixel electrode 110 isnot laid on the highest portion of the intersecting portion 100, so thatthere should not be formed any current path between the black matrix 108and the pixel electrode 110 due to the above-mentioned pressure exertedfrom a spacer.

Actually, however, there may occur a case that the pixel electrode 110is laid on the highest portion of the intersecting portion 100 due to apatterning error, i.e., insufficient patterning accuracy, as shown inFIG. 2B.

In this state, defective portions 115 may occur in the third interlayerinsulating film 109 due to the above-mentioned pressure from a spacer,disabling the black matrix 108 and the pixel electrode 110 to form anauxiliary capacitor.

Although the safest measure is to form the pixel electrode 110 with alarge margin in light of the patterning accuracy, the increase in marginis not desirable in view of a future situation where it will becomedifficult to secure necessary capacitance of the auxiliary capacitor asthe miniaturization of wiring lines proceeds.

SUMMARY OF THE INVENTION

An object of the present invention is to provide, by solving the aboveproblems, a technique for forming a defect-free auxiliary capacitorwhile securing a sufficient area for it. More specifically, an object ofthe invention is to provide a technique for preventing short-circuitingof an interlayer insulating film due to pressure exerted from a spacer.

According to one aspect of the invention, there is provided a liquidcrystal display device comprising an active matrix substrate comprisinga gate line formed on a substrate having an insulating surface; a firstinterlayer insulating film covering the gate line; a data line formed onthe first interlayer insulating film so as to cross the gate line; athin-film transistor formed in the vicinity of an intersecting portionof the gate line and the data line; a second interlayer insulating film;a black matrix made of a conductive material and formed over the gateline and the data line with the second interlayer insulating filminterposed in between; a third interlayer insulating film covering theblack matrix; a pixel electrode being a transparent conductive film andformed on the third interlayer insulating film, the pixel electrodecoextending with the gate line and the data line in areas other than theintersecting portion of the gate line and the data line with theinterlayer insulating films interposed in between; an opposed substratehaving electrodes on a surface thereof; and spacers and a liquid crystalinterposed between the active matrix substrate and the opposedsubstrate.

Further, there is provided a liquid crystal display device comprising anactive matrix substrate comprising a gate line formed on a substratehaving an insulating surface; a first interlayer insulating filmcovering the gate line; a data line formed on the first interlayerinsulating film so as to cross the gate line; a thin-film transistorformed in the vicinity of an intersecting portion of the gate line andthe data line; a second interlayer insulating film; a pixel electrodebeing a transparent conductive film and formed over the gate line andthe data line with the second interlayer insulating film interposed inbetween, the pixel electrode coextending with the gate line and the dataline in areas other than the intersecting portion of the gate line andthe data line with the interlayer insulating films interposed inbetween; a third interlayer insulating film covering the pixelelectrode; a black matrix made of a conductive material and formed onthe third interlayer insulating film; an opposed substrate havingelectrodes on a surface thereof; and spacers and a liquid crystalinterposed between the active matrix substrate and the opposedsubstrate.

In the above liquid crystal display devices, the black matrix, the pixelelectrode, and the third interlayer insulating film form an auxiliarycapacitor.

A corner portion of the pixel electrode is intentionally cut out so asnot to coextend with the intersecting portion of the gate line and thedata line when viewed from above.

The above devices will be described with reference to FIGS. 3A and 3B.FIG. 3A is a sectional view of an intersecting portion 100 of a gateline 104 and a data line 106 and its vicinity in a pixel area. FIG. 3Auses the same reference numerals as FIG. 1A with non-essential parts notgiven reference numerals, because they show similar structures.

The structure of FIG. 3A is different from that of FIG. 1A in that apixel electrode 110 does not overlap with the intersecting portion 100.This structure prevents short-circuiting in an auxiliary capacitor dueto pressure exerted from a spacer, which is the problem described in theabove background description.

FIG. 3B shows a top view of the same structure. That is, FIG. 3A is asectional view taken along a chain line B-B′ in FIG. 3B.

As shown in FIG. 3B, end portions of the pixel electrode 110 coextendwith the gate line 104 and the data line 106. On the other hand, acorner portion of the pixel electrode 110 is intentionally cut out toavoid the intersecting portion 100.

There is another advantage that because the pattern of the pixelelectrode 110 no longer has sharp corner portions, an orientation film(alignment film) which will be later formed so as to cover the pixelelectrode 110 has superior coverage.

According to another aspect of the invention, there is provided amanufacturing method of a liquid crystal display device, comprising thesteps of forming gate lines made of a conductive material on a substratehaving an insulating surface; forming a first interlayer insulating filmso as to cover the gate lines; forming data lines on the firstinterlayer insulating film so that they cross the gate lines; forming asecond interlayer insulating film so as to cover the gate lines and thedata lines; forming a black matrix made of a conductive material on thesecond interlayer insulating film; forming a third interlayer insulatingfilm so as to cover the black matrix; forming transparent conductivefilms as pixel electrodes on the third interlayer insulating film sothat the pixel electrodes coextend with the gate lines and the datalines in areas other than the intersecting portions of the gate linesand the data lines with the interlayer insulating films interposed inbetween; inserting spacers and sealing a liquid crystal between thesubstrate and an opposed substrate having electrodes on a surfacethereof; and forming thin-film transistors in the vicinity of therespective intersecting portions of the gate lines and the data linesthat are arranged in matrix form.

Further, there is provided a manufacturing method of a liquid crystaldisplay device, comprising the steps of forming gate lines made of aconductive material on a substrate having an insulating surface; forminga first interlayer insulating film so as to cover the gate lines;forming data lines on the first interlayer insulating film so that theycross the gate lines; forming a second interlayer insulating film so asto cover the gate lines and the data lines; forming transparentconductive films as pixel electrodes on the second interlayer insulatingfilm so that the pixel electrodes coextend with the gate lines and thedata lines in areas other than the intersecting portions of the gatelines and the data lines with the interlayer insulating films interposedin between; forming a third interlayer insulating film so as to coverthe pixel electrodes; forming a black matrix made of a conductivematerial on the third interlayer insulating film; inserting spacers andsealing a liquid crystal between the substrate and an opposed substratehaving electrodes on a surface thereof; and forming thin-filmtransistors in the vicinity of the respective intersecting portions ofthe gate lines and the data lines that are arranged in matrix form.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show a conventional structure of an intersecting portionof a gate line and a data line and its vicinity;

FIGS. 2A and 2B show a conceivable structure of an intersecting portionof a gate line and a data line and its vicinity;

FIGS. 3A and 3B show a structure of an intersecting portion of a gateline and a data line and its vicinity according to a first embodiment ofthe present invention;

FIGS. 4A-4E show a manufacturing process of thin-film transistorsaccording to the first embodiment;

FIG. 5 shows a general configuration of a liquid crystal display deviceaccording to the first embodiment; and

FIG. 6 shows a structure of an intersecting portion of a gate line and adata line and its vicinity according to a second embodiment of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention as summarized above will be described below indetail by way of embodiments.

Embodiment 1

This embodiment is directed to a process of manufacturing an activematrix liquid crystal display device having thin-film transistors(TFTs). A manufacturing process of a pixel TFT to be formed in a pixelarea and a circuit TFT to be formed in a peripheral driver circuit willbe outlined with reference to FIGS. 4A-4E.

First, a substrate having an insulating surface is prepared. “Substrateshaving an insulating surface” not only means a glass substrate, a quartzsubstrate, and a substrate made of these material on which an insulatingfilm is formed, but also encompasses a silicon substrate and aconductive substrate on which an insulating film is formed.

In this embodiment, a 2,000-Å-thick silicon oxide film as an undercoatfilm 402 is formed on a glass substrate 401 by sputtering or plasma CVD.

Next, an amorphous silicon film (not shown) of 100-1,000 Å in thicknessis formed on the undercoat film 402 by plasma CVD or low-pressurethermal CVD. The amorphous silicon film is crystallized by performing aheat treatment at 550°-650° C. for 1-24 hours or illumination with laserlight in an ultraviolet range, or both. In this step, an element (forinstance, Ni) for accelerating the crystallization may be added.

Next, a crystalline silicon film obtained by crystallizing the amorphoussilicon film is patterned into island-like semiconductor layers asactive layers 403 and 404.

A 1,200-Å-thick silicon oxide film 405, which will serve as a gateinsulating film, is formed over the active layers 403 and 404 by plasmaCVD. Alternatively, a silicon oxynitride (for instance, represented bySiO_(x)N_(y)) film or a silicon nitride film may be used.

Next, a 3,000-Å-thick aluminum film 406 containing scandium at 0.2 wt %is formed. The addition of scandium is effective in suppressingoccurrence of hillocks and whiskers on the surface of the aluminum film406. The aluminum film 406 will serve as a gate electrode.

Instead of the aluminum film 406, a film made of some other metalmaterial such as Mo, Ti, Ta, or Cr, or a conductive film made ofpolysilicon or a silicide material may be used.

Next, anodization is performed in an electrolyte with the aluminum film406 used as the anode. The electrolyte is one obtained by neutralizing(pH=6.92) an ethylene glycol solution containing tartaric acid at 3% byaqueous ammonia. Platinum is used as the cathode. The formation currentand the final voltage are set at 5 mA and 10 V, respectively.

A resulting dense anodic oxide film (not shown) has an effect ofimproving the adhesiveness of a photoresist which will be formed later.Its thickness can be controlled by the voltage application time (seeFIG. 4A).

In this state, the aluminum film 406 is patterned into starting forms ofgate electrodes and gate lines (not shown). Then, second anodization isperformed to form porous anodic oxide films 407 and 408 (see FIG. 4B).

A 3% oxalic acid solution is used as an electrolyte, and platinum isused as the cathode. The formation current and the final voltage are setat 2-3 mA and 8 V, respectively. This anodization proceeds parallel withthe substrate 401. The length of the porous anodic oxide films 407 and408 can be controlled by the voltage application time.

After the photoresist is removed with a dedicated peeling liquid, thirdanodization is performed by using an electrolyte obtained byneutralizing (pH=6.92) an ethylene glycol solution containing tartaricacid at 3% with aqueous ammonia. Platinum is used as the cathode. Theformation current and the final voltage is set at 5-6 mA and 100 V,respectively.

Resulting anodic oxide films 409 and 410 are very dense and strong, andhence provide an effect of protecting gate electrodes 411 and 412 frombeing damaged in later steps such as doping steps.

The strong anodic oxide films 409 and 410, which are hard to be etched,may cause a problem of a long etching time in forming contact holesthrough those films. It is therefore desirable that the thickness ofthose films be less than 1,000 Å.

In the state of FIG. 4B, an impurity is introduced into the activelayers 403 and 404 by ion doping. For example, an impurity of P(phosphorus) may be introduced to form an n-channel TFT, and an impurityof B (boron) may be introduced to form a p-channel TFT.

As a result, source and drain regions 413 and 414 of a circuit TFT andsource and drain regions 415 and 416 of a pixel TFT are formed in aself-aligned manner.

Next, after the porous anodic oxide films 407 and 408 are removed, ionimplantation is performed again. The dose at this time is set lower thanin the previous ion implantation.

As a result, low-concentration impurity regions 417 and 418 and achannel-forming region 421 of the circuit TFT and low-concentrationimpurity regions 419 and 420 and a channel-forming region 422 are formedin a self-aligned manner (see FIG. 4C).

In this state, laser light illumination and thermal annealing areperformed. In this embodiment, the laser light energy density is set at160-170 mJ/cm², and the thermal annealing is performed at 300°-450° C.for one hour.

In this step, the crystallinity of the active layers 403 and 404 thatwere damaged in the ion doping step is improved and the implantedimpurity ions are activated.

Next, a 4,000-Å-thick silicon nitride film (or a silicon oxide film) asa first interlayer insulating film 423 is formed by plasma CVD. Thefirst interlayer insulating film 423 may have a multilayered structure.

Then, contact holes are formed, by etching, through the first interlayerinsulating film 423 at locations corresponding to the source region 413,the gate electrode 411, and the drain region 414 of the circuit TFT andthe source region 415 of the pixel TFT.

Subsequently, laminate films of titanium and a material mainly made ofaluminum are formed as a source wiring line 424, a gate wiring line 425,and a drain wiring line 426 of the circuit TFT and a source wiring line427 of the pixel TFT. At the same time, a data line (not shown) isformed which is connected to the source wiring line 427 of the pixelTFT.

Next, a second interlayer insulating film 428 is formed at a thicknessof 0.5-5.0 μm by plasma CVD. The second interlayer insulating film 428may be either a single-layer film or a multilayer film of a siliconoxide film, a silicon nitride film, an organic resin film, and likefilms.

In particular, the use of an organic resin material such as polyimide ispreferable, because it has a small relative dielectric constant and caneasily provide a thick film and hence capacitances of parasiticcapacitors formed by the above respective wiring lines and a blackmatrix that will be formed later are negligible.

Thus, the state of FIG. 4D is obtained. In this state, a 1,000-Å-thickblack matrix 429 is formed by using a conductive material. The blackmatrix 429 is so shaped as to cover the pixel TFT as well as the gateline and data line (both not shown).

Next, a third interlayer insulating film 430 is so formed as to coverthe black matrix 429. It is preferred that the third interlayerinsulating film 430 be as thin as possible and be made of a materialhaving a large relative dielectric constant (at least larger than thatof the second interlayer insulating film 428). In this embodiment, thethird interlayer insulating film 430 is a 2,000-Å-thick silicon nitridefilm.

Next, contact holes are formed, by etching, through the second and thirdinterlayer insulating films 428 and 430 at a location corresponding tothe drain region 416 of the pixel TFT, and a transparent conductive filmas a pixel electrode 431 is formed. Thus, the circuit TFT and the pixelTFT are formed as shown in FIG. 4E.

Further, the pixel area where the above pixel TFTs are arranged inmatrix form needs to be subjected to a step for introducing and sealinga liquid crystal. This step will be outlined below.

First, in the pixel area, an orientation film (alignment film) is soformed as to cover the pixel electrodes 431. Rubbing is then performedto impart a desired alignment (i.e., orientation) characteristic to theorientation film (alignment film). Thus, the preparation of the activematrix substrate is completed.

Next, an opposed substrate formed with a transparent conductive film andan orientation film (alignment film) that is given a desired alignmentcharacteristic (orientation characteristic) is prepared. If necessary,the opposed substrate may be provided with a black matrix or colorfilters.

The thus-prepared opposed substrate is bonded to the active matrixsubstrate. In the bonding step, spacers are interposed between the twosubstrate to determine the cell gap.

A sealing material is applied to the periphery of the pixel area toprevent the two substrates from disengaging from each other as well asto prevent a liquid crystal, which will be injected later, fromescaping.

After the two substrates are bonded together, a liquid crystal isinjected through an opening of the sealing member and then confined inthe space corresponding to the pixel area. Thus, a liquid crystaldisplay device is completed.

FIG. 5 shows a general configuration of an active matrix liquid crystaldisplay device in which the above-described circuit TFTs and pixel TFTsare arranged. In FIG. 5, reference numerals 501-503 denote a glasssubstrate, a horizontal scanning circuit, and a vertical scanningcircuit, respectively.

Image signals are externally supplied to input terminals 504, and thensent to the pixel electrodes with the pixel TFTs, which are controlledby the horizontal and vertical scanning circuits 502 and 503, serving asswitching elements. Image display is performed by a pixel area 505 byvarying the electro-optical characteristic of the liquid crystal that isinterposed between the active matrix substrate and the opposedsubstrate. Reference numeral 506 denotes common electrodes for applyingpredetermined voltages to the opposed substrate.

The circuit TFTs described in connection with FIGS. 4A-4E can constitutethe horizontal and vertical scanning circuits 502 and 503 in the form ofa CMOS structure in which an n-channel TFT and a p-channel TFT arecombined complementarily.

On the other hand, the pixel TFTs are disposed at the respectiveintersections of the gate lines and the source lines that are arrangedin matrix form, as shown in an enlarged view 507. Thus, the pixel TFTscan be used as switching elements for controlling the amount of chargeentering/exiting from the respective electrodes.

The above-configured device of FIG. 5 operates in the manner as outlinedabove to perform image display. This device is a compact,high-performance panel in which the operation frequency of theperipheral circuits is higher than 3 MHz and the contrast ratio of thedisplay section is higher than 100.

In the pixel area of the above-configured liquid crystal display device,each intersecting portion of a gate line and a data line and itsvicinity assume a structure shown in FIGS. 3A and 3B. FIG. 3B is a topview and FIG. 3A is a sectional view taken along line B-B′ in FIG. 3B.

Although in this embodiment a dense anodic oxide film is formed on thesurface of a gate line 104, it is not shown in FIG. 3A.

With this structure, even if a spacer 112 exists over an intersectingportion 100, no defective portion occurs in a third interlayerinsulating film 109 between a black matrix 108 and a pixel electrode110.

Since the pixel electrode is so patterned as to intentionally avoid onlythe intersecting portion 100, it can be overlapped with the gate line104 and the data line 106, thereby maximizing the capacitance of theauxiliary capacitor.

Even if some patterning error occurs in forming the pixel electrode 110of FIG. 3B, there never occurs an event that the pixel electrode 110overlaps with the intersecting portion 100. Therefore, the problemrelating to the patterning accuracy which is associated with theconventional techniques can be solved.

Although a patterning margin of about several micrometers is needed inlight of the current patterning accuracy, this embodiment can easilyprovide such a margin by virtue of the unique shape of the pixelelectrode 110.

As described above, the manufacturing method of a liquid crystal displaydevice according to this embodiment solves the problems associated withthe conventional techniques, such as short-circuiting in an auxiliarycapacitor or between wiring lines due to pressure that is exerted from aspacer, thereby greatly improving the yield of a manufacturing process.

Embodiment 2

This embodiment is directed to a modification of the pixel electrode ofthe first embodiment. Specifically, a pixel electrode 110 is formed asshown in FIG. 6.

Like FIG. 1B, FIG. 6 is a top view as viewed from above the substrateshowing an intersecting portion of a gate line 104 and a data line 106and its vicinity. Therefore, FIG. 6 uses the same reference numerals asFIG. 1B.

With the shape of the patterning electrode 110 shown in FIG. 6, thepatterning electrode 110 may be so formed as to be spaced from theintersecting portion 100 by a necessary patterning margin and to assumea corner shape similar to that of the intersecting portion 100.

As described above, the invention provides a liquid crystal displaydevice which is free of the problems associated with the conventionaldevices, such as short-circuiting in an auxiliary capacitor or betweenwiring lines due to pressure that is exerted from a spacer, and hencecan greatly improve the yield of a manufacturing process.

What is claimed is:
 1. An electro-optical device comprising: an activematrix substrate comprising: a gate line formed on a substrate having aninsulating surface; a first interlayer insulating film covering the gateline; a data line formed on the first interlayer insulating film so asto cross the gate line; a thin-film transistor formed in the vicinity ofan intersecting portion of the gate line and the data line; a secondinterlayer insulating film; a pixel electrode being a transparentconductive film and formed over the gate line and the data line with thesecond interlayer insulating film interposed in between, the pixelelectrode coextending with the gate line and the data line in areasother than an intersecting portion of the gate line and the data linewith the interlayer insulating films interposed in between; a thirdinterlayer insulating film covering the pixel electrode; a black matrixmade of a conductive material and formed on the third interlayerinsulating film; an opposed substrate having electrodes on a surfacethereof; and spacers and a liquid crystal interposed between the activematrix substrate and the opposed substrate.
 2. A device according toclaim 1, wherein the black matrix and the pixel electrode form anauxiliary capacitor with the third interlayer insulating film inbetween.
 3. A device according to claim 1, wherein a corner portion ofthe pixel electrode is intentionally cut out so as not to coextend withthe intersecting portion when viewed from above.
 4. A manufacturingmethod of an electro-optical device, comprising the steps of: forminggate lines made of a conductive material on a substrate having aninsulating surface; forming a first interlayer insulating film so as tocover the gate lines; forming data lines on the first interlayerinsulating film so that they cross the gate lines; forming a secondinterlayer insulating film so as to cover the gate lines and the datalines; forming transparent conductive films as pixel electrodes on thesecond interlayer insulating film so that the pixel electrodes coextendwith the gate lines and the data lines in areas other than intersectingportions of the gate lines and the data lines with the interlayerinsulating films interposed in between; forming a third interlayerinsulating film so as to cover the pixel electrodes; forming a blackmatrix made of a conductive material on the third interlayer insulatingfilm; inserting spacers and sealing a liquid crystal between thesubstrate and an opposed substrate having electrodes on a surfacethereof; and forming thin-film transistors in the vicinity of therespective intersecting portions of the gate lines and the data linesthat are arranged in matrix form.
 5. A method according to claim 4,wherein the black matrix and the pixel electrodes form auxiliarycapacitors with the third interlayer insulating film in between.
 6. Amethod according to claim 4, wherein corner portions of the pixelelectrodes are intentionally cut out so as not to coextend with theintersecting portions when viewed from above.